Shelby County, AL Roof Snow Load - 5 psf
How much snow is too much for a roof in Shelby County, AL?
5 psf: that's what ASCE 7-22 requires a typical heated home's roof in Shelby County to carry. The physics-based figure alone would be 3.5 psf, but ASCE 7's own low-slope minimum (§7.3.4) sets a floor of 5 psf for flat and low-pitch roofs here, which is the number that actually governs.
Picture it, not just weigh it: 11 in. if it's fresh powder, 4 in. once it settles, or a mere 1 in. if it's ice. This is a modest add-on to standard roof loading - ordinary residential construction carries it without extra bracing.
Shelby County in numbers
- Design roof snow load5 psf
- Ground snow load, ASCE 7 map5 psf
- National rank#2,095 of 2,758
- Alabama rank#20 of 67
- Population235,969
- Annual snowfall, NOAA normal0 in.
- FIPS01117
How Shelby County compares
5 psf ranks #2,095 of 2,758 US counties with a mapped snow load (top 76%) - and #20 of 67 in Alabama. 5.6 psf is Alabama's typical county figure - Shelby County comes in 0.6 psf under it.
Population 235,969 (FIPS 01117), roughly 33.2669°N 86.661°W. The 5 psf ground snow load ASCE 7-22 maps here becomes 5 psf once the code's own design factors are applied.
Typical snowfall in Shelby County, AL
NOAA's 30-year normal for Shelby County: 0 in. of snow a year, from the LEEDS, AL US station. (fresh vs. packed vs. ice explains why.)
What this Shelby County figure assumes
This is a county-level reference figure for a typical heated home built to Risk Category II (ordinary residential), on a partially exposed lot - the assumptions ASCE 7-22 itself treats as the default case. A steeper roof, a fully exposed hilltop lot, an unheated structure, or a higher risk category all change the actual number.
Shelby County's permit office wants an address-specific figure, not this county average - the ASCE 7 Hazard Tool is free, takes under a minute, and outputs a PDF most reviewers accept. (How this figure is calculated.)